When Lost returns next month, you'll be seeing lots of familiar faces turning up... including a few you might have forgotten. But does Lost have the biggest cast of recurring characters of any science-fiction show? The answer might surprise you.

The sprawling ensemble cast is a hallmark of the modern-day science fiction series. Shows like Lost, Babylon 5, The X-Files, Star Trek: Deep Space Nine and Battlestar Galactica have featured tons of characters who show up for a few episodes, then vanish... only to reappear, with sudden significance, a year or two later. The hitherto unsuspected connection between two random characters is a hallmark of these shows, and so is the chance meeting between two previously unconnected characters.

So which shows of the past two decades have the biggest casts of recurring characters? We looked at IMDB, to find out. Our criteria: Someone had to have turned up in three episodes or more, and young/alternate versions of the same character didn't count. So who's got the biggest ensemble cast? Here's our list, from least to most.

Farscape: 48 characters

You've got a dozen or so regulars, plus people like Jack Crichton, Minister Akhna, Ka Jothee, Bekhesh and Emperor Staleek.What if you drop it to just people who've been in five or more episodes? Then you've got just 24 recurring characters.

Battlestar Galactica: 64 characters

This includes all of the regulars that you know and love, plus various delegates, mining ship workers, random pilots, family members and people who've turned up in flashbacks (like Zak Adama.) There's Gonzo Pike and Romo Lampkin, and of course Hera Agagathon. And don't forget Skulls, Crashdown, Jammer, Hotdog and Narcho (?).What if you drop it to just people who've been in five or more episodes? Then it's just 42 characters.

Star Trek: Deep Space 9: 70 characters

Just the station staff, and their families, account for a huge number of characters. Then you've got the random Bajorans, Cardassians, Founders, Klingons and other parties in the huge sprawling war story that takes up half the show's run. There's Rom, Nog, Morn, various Siskos, Ziyal, and don't forget Vic Fontaine.What if you drop it to just people who've been in five or more episodes? Then it's just 40 characters.

Bablyon 5: 70 characters

The main cast is fairly large, if you include characters like Kosh, Na'Toth, Talia Winters and Marcus Cole. And then there are a number of ambassadors and staff who turn up regularly. There's also Alfred Bester, the ISN Anchor, Lorien, and a slew of support staff.What if you drop it to just people who've been in five or more episodes? Then it's 44 characters.

Lost: 91 characters

I know: just 91? It seems like it should be more. Besides the survivors of Oceanic 815 and Desmond, there are various Others and Dharma people, plus friends and family off-Island. We do know that there will be a few new chracters in season six who will turn up in multiple episode, so that number will definitely go up.What if you drop it to just people who've been in five or more episodes? It goes down to 60.

Smallville: 103 characters

Why so many? There are a ton of recurring villains, like Metallo, Zod, Doomsday, Brainiac, and Toyman. There are recurring superheroes like John Jones and Bart Allen, plus varous family members and friends of the core cast.What if you drop it to just people who've been in five or more episodes? Down to a mere 33 characters.

Heroes: 115 characters

Not including "Young Hiro" and "Young Samuel," there are 115 characters who've appeared in three or more episodes. That includes the core cast of characters, various love interests like Gretchen, Elle, Charlie, and Caitlin the Irish alt-universe castaway, and family members like Maury Parkman, the Nakamuras, and the Dawson clan. Plus various cops, carnies, agents of the Company, and so on.What if you drop it to just people who've been in five or more episodes? Then it drops to 63 characters.

The X-Files: 143 characters

Over 201 episodes, this show had plenty of scope to introduce tons of characters who popped up from time to time, including obvious ones like Cigarette-Smoking Man and the Lone Gunmen, but also Alien Bounty Hunter, various Scully and Mulder family members, and a host of detectives and FBI agents.What if you drop it to just people who've been in five or more episodes? Then it drops to just 47 characters.

Stargate SG-1: 144 characters

With 211 episodes, it's not surprising this show had the most recurring characters. Only 22 characters are in more than a dozen episodes, including the main SG-1 crew, support staff, and the most frequently appearing antagonists. After that, you've got a lot of support staff, occasional villians, and characters like Richard Woolsey and Lantash.What if you drop it to just people who've been in five or more episodes? It drops to just 67 characters.

Did we leave out any shows with humongous casts? Weigh in in the comments.

Note: It's harder to do this sort of number crunching for animated series, but Wikipedia lists 19 main or secondary characters in Futurama, plus 39 "minor" characters. And there are approximately 62 recurring Venture Bros. characters.